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AssigneeYamato Scale Company, Limited
InventorsShozo Kawanishi, Kazuo Usui, Atsushi Watanabe
Estimating the term…
A powder-weighing apparatus and a powder-weighing method having a high weighing speed and a high weighing accuracy are provided. For weighing powder within a predetermined allowable range of a target weight Wt, the powder-weighing apparatus may be configured to have a primary-charge weighing portion for weighing and retaining a weight W1 of primary-charge powder smaller than the target weight Wt and at least two auxiliary-charge weighing portions each for weighing and retaining a weight W2 of auxiliary-charge powder within a predetermined range of an auxiliary-charge weight Ws. When a weight W1 of the powder retained in the primary-charge weighing portion is smaller than a lower limit of the predetermined allowable range of the target weight Wt, one of the two weights W2 may be selected so that a sum (W1+W2) becomes closest to the target weight Wt, and the powder retained in the primary-charge weighing portion and the powder retained in the selected auxiliary-charge weighing portion are discharged.
A powder-weighing apparatus for weighing powder within a predetermined allowable range of a target weight Wt, the apparatus comprising:
A powder-weighing apparatus for weighing powder within a predetermined allowable range of a target weight Wt, the apparatus comprising:
A powder-weighing apparatus for weighing powder within a predetermined allowable range of a target weight Wt, the apparatus comprising:
A powder-weighing method for weighing powder within a predetermined allowable range of a target weight Wt, the method comprising the steps of:
A powder-weighing method for weighing powder within a predetermined allowable range of a target weight Wt, the method comprising the steps of:
A powder-weighing method for weighing powder within a predetermined allowable range of a target weight Wt by weighing primary-charge powder smaller than the target weight Wt and at least two auxiliary-charge powders within a predetermined range of an auxiliary-charge weight Ws, the method comprising the steps of:
Dependencies are inferred from the claim text.
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Weighing
Term end not estimated
The present invention relates to a powder-weighing apparatus and a powder-weighing method, and more specifically to a powder-weighing apparatus and a powder-weighing method that are capable of weighing a powdery or granular article with a high degree of accuracy by separately weighing a powder for primary-charge and at least two powders for auxiliary-charge.
Conventionally, a powder-weighing apparatus shown in FIG. 4 has been used to weigh powder. This powder-weighing apparatus includes a weighing hopper 13 for retaining powder. Powder is charged from a charging device 15 to this weighing hopper 13, and a load cell 12 measures the weight of the powder retained inside the weighing hopper 13. As such a powder-weighing apparatus, a weighing apparatus having a two-stage charge system has been employed to improve its weighing speed and weighing accuracy. FIG. 5 shows a relationship between charge amounts, charge flow rates, and charge times in the two-stage charge system. As shown in FIG. 5, in a weighing apparatus having a two-stage charge system, for the purpose of increasing its weighing speed, powder is charged into a weighing hopper at a high flow rate until a weighed value of the powder reaches approximately 90% of a target weight (100%) (quick-charge step), and the remaining 10% of the powder is charged into the weighing hopper at a low flow rate (slow-charge step).
In such a weighing apparatus having a two-stage charge system, ways to further increase its weighing speed while maintaining its weighing accuracy are, for example, (1) to further increase a powder amount to be charged in a quick-charge step from the above-mentioned approximately 90%, or (2) to increase a flow rate of powder to be weighed in a quick-charge step. However, in (1), where a powder amount to be charged in a quick-charge step is increased, overshooting takes place during the changeover from a powder flow rate in the quick-charge step to a powder flow rate in the slow-charge step, resulting in a situation in which the slow-charge step is not executed because the target weight is assumed to be reached. In this case, a final weight of the powder to be obtained is far below the target weight. Similarly, in (2), where a powder flow rate in a quick-charge step is increased, overshooting takes place during the changeover from a powder flow rate in a quick-charge step to a powder flow rate in a slow-charge step, thereby resulting in a situation in which a final weight of the powder to be obtained is below the target weight. In addition, since a controller is necessary to change over from a quick-charge step to a slow-charge step, there is such a drawback that the cost of the weighing apparatus becomes high. Furthermore, since the time-consuming slow-charge step must be executed to ensure the weighing accuracy, there is such a problem that the weighing speed can not be increased above a certain level.
FIG. 1 is a side elevation view schematically showing a general constitution of a powder-weighing apparatus according to one embodiment of the present invention;
FIG. 2 is a side elevation view schematically showing a general constitution of a powder-weighing apparatus according to another embodiment of the present invention;
FIG. 3 is a view showing a weighing accuracy distribution in a case where the powder-weighing apparatus shown in FIG. 1 is used to perform weighing;
Hereinbelow, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side elevation view schematically showing a general constitution of a powder-weighing apparatus according to one embodiment of the present invention. The powder-weighing apparatus 10 according to the present embodiment weighs powder within a predetermined allowable range of a target weight Wt and has a primary-charge weighing portion 21 and a first auxiliary-charge weighing portion 31 and a second auxiliary-charge weighing portion 41. The primary-charge weighing portion 21 includes a primary-charge weighing hopper 13 and a load cell 12 for measuring the weight of powder retained in the primary-charge weighing hopper 13. A gate 14 for discharging powder is provided in a lower portion of the primary-charge weighing hopper 13. The first auxiliary-charge weighing portion 31 includes a first auxiliary-charge weighing hopper 33 and a load cell 32, and the second auxiliary-charge weighing portion 41 includes a second auxiliary-charge weighing hopper 43 and a load cell 42. Furthermore, the powder-weighing apparatus 10 according to the present embodiment has a primary-charge weighing hopper 13 and a charge device 15 for charging powder into the first auxiliary-charge weighing hopper 33 and the second auxiliary-charge weighing hopper 43.
In the powder-weighing apparatus 10 according to the present embodiment, powder is charged aiming at a target weight Wt as target from the charge device 15 into the primary-charge weighing hopper 13 of the primary-charge weighing portion 21 and the first auxiliary-charge weighing hopper 33 of the first auxiliary-charge weighing portion 31. According to the present embodiment, the first auxiliary-charge weighing hopper 33 is set such that powder is charged aiming at an auxiliary-charge weight Ws as target. An actual primary-charge powder weight W1 charged into the primary-charge weighing hopper 13 is measured by the load cell 12, and an actual primary-charge powder weight W21 charged into the first auxiliary-charge weighing hopper 33 is measured by the load cell 32.
Also, into the second auxiliary-charge weighing hopper 43, powder is charged from the charge device 15 aiming at the same auxiliary-charge weight Ws as the weight of powder charged into the first auxiliary-charge weighing hopper 33 as target. An actual auxiliary-charge powder weight 22 charged into the second auxiliary-charge weighing hopper 43 is measured by the load cell 42.